Evaluation of a Cement Dust Generation and Exposure Chamber for Rodents: Blood Heavy Metal Status, Haematological Variables and Gastrointestinal Motility in Rats

Exposure to cement dust has been documented to cause various occupational and long-term health complications both in human and animal. However, investigations on the extent of toxicity associated with cement dust exposure have been limited by lack of suitable model for controlled laboratory exposures. In this study, a glass house animal exposure chamber was fabricated using a plexi-glass and a blowing fan of adjustable revolution. Model simulations were validated using experimental data showing the effects of cement dust exposure on hematological indices, trace element status and gastrointestinal motility in rats.   Thirty male Wistar rats were randomly divided into three groups. The unexposed group (n = 10) served as control while the other groups were exposed for five hours daily to cement dust (200g) at a revolution of 2400-3000rpm. Blood collected was analyzed for some hematological variables as well as plasma concentrations of cadmium, lead, silicon, aluminum, manganese, calcium, iron and magnesium. Organ weights were measured and histopathological features of the kidney, lungs stomach and liver were assessed to determine the degree of tissue damage. Data were expressed as Mean ± SEM, analysed using one-way ANOVA and p0.05 was significant.   Blood analysis from exposed rats on days 14 and 28 showed significant increase in concentrations of Calcium, Silicon, Manganese, Iron, Lead, Cadmium, Aluminum and magnesium compared with unexposed animals. Significant reductions were observed in hematocrit values, red and white blood cells counts after cement dust exposure. Also, significant increases were observed in the neutrophil-lymphocyte ratio and erythrocyte sedimentation rate in exposed rats compared with control. There was a significant decrease in organ weights - stomach, lungs, kidney when compared with control. Histopathological examination from exposed rats revealed peribronchiolar infiltration by lymphocytes in the lungs while gastric gland was severely infiltrated by inflammatory cells.   The results from this study are comparable to data obtained from earlier reported on hematological and heavy metals in humans occupationally exposed to cement